Discharge device



Jan. 23, 1940. A. .1. KLING 2,188,186

DISCHARGE DEVICE Filed Jain. 20, 1959 In ventor:

August J. KH lg,

' 8 His Attorney.

Patented Jan. 23, 1940 UNITED STATES PATENT OFFICE General ElectricCompany,

New York a corporation of Application January 20, 1939-, Serial No.251,979

8 Claims.

The present invention relates to improved means for introducing anactive substance into a sealed discharge device at a particular timeduring the fabrication or use thereof.

Numerous methods have been proposed for introducing a substance such asa getter or photosensitivematerial into the interior of a dischargedevice after the same has been evacuated and sealed. Most of the knownsystems, however, 10 function satisfactorily only when relatively smallquantities of the active element are needed. It is one object of mypresent invention to provide an improved means which will serve withequal effectiveness whether large or small quantities are 15 to be dealtwith.

To this end the invention provides a substanceenclosing capsule orcontainer which comprises a readily frangible wall portion.Temperatureresponsive means, directly mechanically con- 20 nected to thesaid wall portion, serve to deform and break the same when it is desiredto liberate the contents of the container. It is a particular advantageof this combination that it is highly dependable and consistent in useso as to be well 5 adapted to the requirements of mass productionprocedure.

The novel features which I desire to protect herein are pointed out withparticularity in the appended claims. The invention itself together withfurther objects and advantages thereof may best be understood byreference to the following description taken in connection with thedrawing in which Fig. 1 illustrates a discharge device suit ablyembodying the invention; Figs. 2 and 3 3; illustrate an importantelement of the embodiment of Fig. 1 in two conditions of use; Fig. '4 isa sectional view taken on line 4-4 of Fig. 2, and Figs. 5 and 6illustrate modifications of the invention.

In the description which follows, the invention is discussed mainly asapplied for the purpose of introducing a getter material into a vacuumtube. It should be understood, however, that it is considered to haveequal application in any other situation where it is desired tointroduce an active material into a sealed discharge envelope at someparticular time during the fabrication or use of the envelope. Oneexample of such a further use is the introduction into a photo tube of ian electrode-sensitizing substance, such, for instance, as calcium.Another example consists in the introduction of a measured quantity of agas such as argon or of a vaporizable ionizing material such as mercuryor sodium into a device such 53 as a discharge lamp or a gaseousrectifier.

readily broken, it may be provided with a cut or Referring particularlyto Fig. 1, there is shown a vacuum tube comprising a base portion ID anda sealed evacuated envelope H. The envelope is provided with a reentrantstem press l2 from which is supported appropriate electrode structure.-In the case illustrated, this structure ineludes an anode or plate 13which is supported from the press l2 by means of conductive stayrods Mand I5. Within the anode,fwhich may consist, for example, of carbonizednickel, there "1'0 are provided in concentric relation, a grid l6 and acathode 11, these being shown in dotted outline. Lead-in connections l8,passing through the press 12, are provided for these various elements.1%

As is well known, in the fabrication of a device such as thatillustrated, it is desirable after the discharge envelope ispreliminarily evacuated and sealed, to introduce into the envelope agetter which acts to absorb or combine with occluded Q0 gases. In orderthat the getter may be brought into contact with the gaseous contents ofthe envelope only at the desired time, it is necessary that it be in thefirst instance isolated from the envelope interior. However, when theappropriate time arrives, some mechanism must be provided foreliminating the isolating means.

In the arrangement shown in Fig. 1, the isolating function isaccomplished by means of a small container or capsule 26 which ismounted on the '30 rod l5 in a position somewhat spaced from theelectrode structure. This is adapted to enclose in sealed relation asuitable getter material. A getter of the type in question may comprise,for example, an alkaline earth metal, such as barium. .35

For the purposes of the present invention the capsuleiil is constitutedof a readily frangible material, such, for example, as glass or quartz.Further, in order that the container may be scratch such as is indicatedat 2| (Fig. 2) so as to decrease the mechanical strength of thecontain'er well.

As a positive means for breakingthe capsule 26 when such breakage isdesired, my invention 3 provides a temperature responsive member whichis operable upon the application of heat to exert a gradually increasingforce upon the capsule 29 so as to deform the capsule sufliciently tofracture the same. The temperature responsive mem- 51' her referred tomay comprise a thermostatic expansion element of known type, such forexample, as a bimetallic strip 23. This is rigidly connected to thecapsule 20 at one end by means of aclamping ring 24. At the other end, alost-motion container need be so constituted.

connection or linkage is provided in the form of a metal loop which isfixed to the expansible element 23, but which engages the capsule 20only after a predetermined deflection of the element. It is the functionof the lost motion connection to permit at least some heating of theexpansion element 23 (e. g. during degassing of the electrodes) withoutcausing fracture of the capsule 20. The character of this connection isillustrated most clearly in Fig. 4.

As is well known, anexpansion element of the type referred to may beformed by combining two elements of diiferent expansion characteristics.One mode of combination is illustrated in Fig. 2 wherein it appears thatthe element 23 includes two metal strips (numbered 23 and'23'respectively) which are placed in face-to-face relation and joinedrigidly throughout their length, as for instance, by brazing. One stripmay comprise a low expansion substance such as Invar, and the other mayconsist of a high expansion substance such as brass. The particularsubstances selected will, of course, depend upon the conditions underwhich the device is to be used.

' In the use of the device described the electrode structure first isheated sufilciently to cause it to release occluded gases. Thereafter,the temperature responsive member 23 is heated, for example, byinduction, to a temperature at which it is caused to undergo a markedlateral deflection. Under these circumstances, the loop 25 .movessufliciently to engage the capsule 20, thus causing its fracture at theweakened region 2|. By this action the substances within the capsuleare, of course, exposed to the interior of the discharge envelope andenabled to react with its contents.

It is not necessary in all cases that the entire body of the containerfrom which the active substance is to be liberated be constituted of afrangible material. In Fig. 5 I have shown an alternative arrangementwherein only a portion of the In this case the container, indicated bythe numeral 26, may be provided with a slender, normally sealed tubulation 21, which is readily breakable by virtue of its small dimensions.With this arrangement, only the part 21 needs to be connected to thetemperature-responsive member (indicated at 28). It will be understood,of course, that breakage of the tubulation 21 by the action of thismember will place whatever material is enclosed in the container 26 incommunication with the interior of the discharge envelope.

A still further application of the invention is shown in Fig. 6 whereinthe main body of the substance-enclosing container is arranged outsidethe discharge envelope as shown at 29. It is, however, adapted tocommunicate with the interior of the envelope through a frangibletubulation 30. This tubulation is normally closed but is provided with atemperature-responsive member 3| which functions when heated to fracturethe tubulation.

It will also be understood that it is not essential to the purposes ofthe invention that the temperature-responsive element employed be of thebimetallic type. One may employ alternatively, for example, a deformabledisk of the character frequently employed in heating appliances.

\ Again, expansion means may be employed which depend on longitudinalrather than lateral expansion.

While I have described my invention in connection with particularstructural embodiments supply of a substance desired to be introducedinto the envelope at a particular time during the fabrication or usethereof, a container having a readily frangible wall part normallyisolating the said substance from theinterior of the envelope, atemperature responsive member which is deformable upon the applicationof heat, and a permanent mechanical connection between the said memberand said frangible wall part effective upon deformation of the member tofracture the said wall part and thereby to place the said substance incommunication with the envelope interior.

2. An electric discharge device including an envelope which encloseselectrode structure, a sealed container Within the envelope andenclosing a quantity of a substance which is desired to be introducedinto the interior of the envelope at some particular time during itsfabrication or use, at least a portion of the said container being ofreadily frangible construction, and a temperature-responsive memberdirectly mechanically connected to the said container and operable uponthe application of heat to deform the said frangible portion of thecontainer sufliciently to fracture the same.

3. An electric discharge device including an envelope which encloseselectrode structure, a capsule Within the envelope enclosing a substancewhich is desired to be introduced into the interior of the envelope atsome particular time during the fabrication or use of the dischargedevice, the said capsule having at least a portion thereof constitutedof readily frangible material, a temperature responsive member which isdeformable upon the application of heat, and a mechanical linkageproviding a direct connection between the said member and the capsuleand efiective upon deformation of the member to cause breakage of thesaid frangible portion of the capsule.

4. An electric discharge device including an envelope which encloseselectrode structure, a supply of a substance desired to be introducedinto the envelope at a particular time during the fabrication or usethereof, a container having a readily frangible wall part normallyisolating the said substance from the interior of the envelope, anelongated bimetallic expansion element adapted to deflect laterally uponthe application of heat, and a mechanical connection between,

the said element and the said frangible wall part effective upon. apredetermined deflection of the element to fracture the said wall partand thereby to place the said substance in communication with theenvelope interior.

5. An electric discharge device including an envelope which encloseselectrode structure, a supply of a substance desired to be introducedinto the envelope at a particular time during the fabrication or usethereof, a container having a readily frangible wall part normallyisolating the said sub-stance from the interior of the envelope, atemperature-responsive member adapted to deform when heated andeffective upon the occurrence of a predetermined deformation thereof tofracture the said wall part of the container, and a lost motionconnection between the said member and the said frangible wall part forpermitting at least some deformation of the member without causingfracture of the wall part.

6. An electric discharge device including an envelope which encloseselectrode structure, an elongated glass capsule within the envelope andenclosing a' quantity of an active substance, the

said container being readily frangible upon the application of lateralforce, and an elongated bimetallic element arranged adjacent to the saidcapsule and secured to the capsule at at least two points along itslength, the said element being adapted to deflect laterally when heatedand thereby to apply sufficient force to the capsule to fracture thesame.

7. An electric discharge device including an envelope which encloseselectrode structure, a sealed container within the envelope enclosing aquantity of an active substance, said container comprising a bulbousportion and an elongated tubulation communicating with the bulbousportion, the said tubulation being of such small dimension as tofacilitate fracture thereof upon the application of lateral force, and atemperature-responsive device permanently mechanically connected to thetubulation and operable upon the application of heat to apply agradually increasing force to the said tubulation to fracture the same.

8. An electric discharge device including an envelope which encloseselectrode structure, a container appended externally to the envelope, asupply of an active substance enclosed by the container, an elongatedtubulation of small transverse dimensions extending between the saidcontainer and the interior of the envelope, the said tubulatio-n beingnormally sealed, and a temperature-responsive device directlymechanically connected to the said tubulation and effective upon theapplication of heat to applya gradually increasing lateral force to thetubulation to fracture 20 the same.

AUGUST J. KLING.

